Traffic Demand Dynamics During Urban Freeway Short-Term Lane Closures

The Texas Transportation Institute (TTI) 2007 mobility report shows traffic congestion is worsening in American cities of all sizes, creating $78 billion annual lost hours and 2.9 billion gallons of wasted fuel per year. Meanwhile, aging roadway infrastructure needs to be frequently maintained to sustain their quality service for the traveling public. Compared to long-term construction zones, short-term work zones (6~8 hours long) are more frequent, but do not receive equal attention due to their low impact. Lane restriction or closure, however, is still inevitable for most maintenance activities and delay may happen even during off-peak periods. The accumulated impact of short-term closures due to their high frequency on a segment cannot be overlooked; especially if the segment carries large traffic volume during peak hours and/or off peak hours.

By using lane closure information and traffic data from the southeastern Wisconsin freeway systems, this study aimed to obtain a clear understanding of the dynamic nature of traffic demand and quantify it as a function of driver characteristics and corridor features. To be specific, the results of the study identify that, in general, a low density of signalized intersections along the arterial routes, high historical mainline traffic, and a short alternative route distance encourage drivers to divert. Consequently, traffic impacts at off-ramp terminals and arterial streets can be estimated via regression models, which in turn assist with informed decisions such as the deployment of advanced traveler information systems.